A telephone system, in its most basic form, comprises one individual dialing a telephone number assigned to another individual. With such a system there is a one-to-one relationship between the dialed number and the destination. The telephone system is also designed to provide special calling services using special inbound telephone numbers. These numbers currently utilize the area codes 700, 800, 888, or 900. Particularly, businesses arrange for the use of a particular 800 or 888 number to allow customers, at no cost, to call and transact business. Conversely, with a 900 number the customer is charged for the service.
During the early 1980's , the long distance carriers removed 800 number translation and routing from switching systems and instead placed it in a call routing database, referred to as a "service control point" (SCP). This architectural implementation allowed a single nationwide free calling number to be routed to any one of a plurality of subscriber destinations. For example, a caller may wish to place an order with a company, inquire about the status of an account, or obtain information about the company's products or services. The SCP must be configured to make the determination as to which of the destinations should receive a particular call, i.e. where the call should be routed. The general type of subscriber service desired may be selected by dialing a particular number, with different numbers corresponding to different services. Alternatively, subscriber may have a single number and utilize prompting whereby additional digits are entered by the caller to specify the particular service desired. All of this information was used by the SCP to make the routing decision.
In response to a call routing inquiry from a carrier switched node, the SCP makes the routing decision based on some combination of specified criteria, namely, originating area code and/or exchange, time of day, day of week, date, and any caller entered digits. These call characteristics are compared to call screening criteria resident in the SCP in the form of a "routing tree" to determine the destination to which the call should be routed. The call routing response results in the call either being routed to a specific location or allocated among a set of locations using preselected percentages. The subscriber may change the call screening process and call allocation percentages by inputting these changes to the SCP in the form of a newer revised routing tree.
U.S. Pat. No. 5,452,350, assigned to the assignee of the present application, disclosed an improvement in routing systems in which routing decision were made outside of the public switched telephone network. Under that system, calls could be routed based on the availability of agents or other resources for handling the calls. Calls were load balanced across multiple subscriber resources at the same or different locations to minimize queuing and maximize resource productivity. Based on screening performed on call characteristics and caller attributes, several subscriber resources could handle the call. Additional criteria provided by the subscriber specifies how to choose among the alternate resources. This criteria included precedence level information used to rank the alternate resource and performance information used to determine the maximum time callers were allowed to wait in queue for each resource at each destination.
With such prior systems, once a routing decision was made, then the call was routed to the selected destination. There was no opportunity for the selected destination to participate in the decision. Once the call is received, then the call could not subsequently be rerouted using the same criteria without the caller terminating the call and placing a new call.
The present invention provides improvements over prior art call routing systems, as discussed more specifically below.